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Build Your Own 10Mbit/sec Optical Data Link
redcliffe writes: "This website has complete plans to build a 10 megabit per second optical data link that can work over up to 1 kilometre. It uses fairly cheap components, such as standard LED's instead of laser diodes. This also makes it a lot safer to work with, i.e. you won't burn your eyes out if you accidently look into it."
And does it have the option of an optical 100MB switch? Or perhaps an interface to isolinear chips?
that can work over up to 1 kilometre
Way to go, "editors"!
The equiptment is cheaper easier to make/get and can get further range. I can get upto 15 miles in Houston with 2 15db direction antennas that you can get for 40$ a peice.
This also makes it a lot safer to work with, i.e. you won't burn your eyes out if you accidently look into it.
Well where's the fun in that?
you wont be able to see em from 1km away, so how would you kow where to aim the things?
Well, what happens if you have an infestation of pigeons around where you live? LED's aren't easy to clean if they're in a tube
you can use the laser diode from any laser pointer that costs$20.
Who needs eyes?
http://www.tiresias.org/equipment/eb2.htm
You'll shoot your eyes out! You'll shoot your eyes out!
"This also makes it a lot safer to work with, i.e. you won't burn your eyes out if you accidently look into it."
It looks as if the author has learned this first hand if the font size on the instructions is any indication.
Check out Grub!
um... immune to interference? So, you've got a link going to the divorcee down the block and the two of you are getting naked on-cam, and the blinds are open (of necessity) and you don't think the little crowd of neighborhood kids at your window is going to interfere?
It uses fairly cheap components, such as standard LED's instead of laser diodes. This also makes it a lot safer to work with, i.e. you won't burn your eyes out if you accidently look into it.
The mere fact lasers are used in most fiber optics does not immediately render them dangerous. Typical power levels are on the order of a few mW, far too low to cause any permanent damage.
Tarsnap: Online backups for the truly paranoid
This is absolutely great! A primo example that goes back to the roots of Slashdot.
Excellent link, great article.
Now where's my soldering gun?
:-)
Eddy.WriteLinux.Com
Do you have any links for sites on 802.11b? And which directional antennas are you using?
Why would the visibility matter, if they are using common radio shack led's ?
for my info...
Reminds me of my favorite warning sticker:
Despite how effective the sticker was at reminding us to keep our goggles on, the safety people made us take it down.As with everything in life, my time is often worth money. So who wants to be the first to tinker around and start churning these out?
------
Today's Top Deals
The article quite clearly states that for 10M, they use a laser diode...
From the "Making the electronics" section (emphasis mine, of course):
Solder remaining parts into the transmitter. Put the three 74HC04's in stack (like they are fucking), and solder pins of equal numbers together. The schematic follows.
Nice.
What's the point of all this? You can just run ethernet over fiber, and a lot longer distance than 1km. You can also get ethernet in a whole lot better than 10Mbps these days.
The equipment is perfectly standard, and if you count your time, a whole lot cheaper.
Has anyone else bothered to read this enough to notice that it will not work with twisted pair Ethernet? It requires an AUI connection. They even say in the FAQ, redesigning it to work with TP would be a pain in the arse.
In order to use the circuit, you have to either buy an AUI->TP transciever, or set up a bridging machine.
Just saving a bit of time for some people who are no doubt running out to Ripoff Shack grabbing l33t bl00 leds.
hint: they are using a fresnel lens to collimate the beam
Others have done similar things with the AUI interface. Here's an RF link using the same technology.
If you want more range from the optical link, I'd suggest putting an optical interference filter (from Edmund Scientific) in front of the receiver. Pick one that matches the color of the transmitted beam, and you'll reject most other light.
You can't actualy go blind from looking at the sun. I have no idea where that idea came from. I looked into the sun all the time as a kid. It hurt a little and can degrade your vision if you do it a lot, but it isn't going to be the last thing you ever see. Evolution isn't that stupid.
autopr0n is like, down and stuff.
I don't know how they're going to use a laser pointer worth a few bucks to compete against a $17000 optical transponder module, much less guarantee any easy replaceability or how they will optically couple the fiber to the LED. Presumably, they could use a high-powered infrared LED, but then the problem is finding a single-mode fiber capable of working in the LED's wavelength with all of the funky effects that go on with the analog design of these things. This isn't going to be a 2N2222 driving a resistor with an LED, that's for sure.
Not only this, but what are they going to use for the underlying switch fabric at both ends? It isn't going to be a PCI card in an Athlon box, that's for damn sure. Fortunately, there is cheap 10G Ethernet silicon but it is neither trivial to use nor design a board with high-speed serial traces that require length matching and careful layout for noise immunity, since all of the 10G links today are designed with high-speed serialization built in. Building an XSBI to LED link isn't exactly the most trivial application, especially in hardware. *chuckle* I had customers who were scrambling to build 10G demo boxes in time for Interop a few months back, and only one made it.
I wish 'em luck, but I seriously doubt they will ever commercialize this, much less succeed in the interim. I hope I'm proven wrong, though.
These, or higher-speed commercial point-to-point transmitters, seem like a neat way to set up a wireless backbone for a (community) wireless network. Then you just hang WiFi transmitters off the backbone access points. Actually, I'd want something a bit faster than 10Mbps for a backbone (aggregate multiple transmitters?), but you get the idea. I'm not sure it'd be superior to using the new 802.11a 5GHz gear for such a backbone, but in either case, you avoid dealing with the local telco monopoly, which is always a Good Thing.
:-).
Maybe put small caching proxy servers at the access points backed up by a big one at the end of the network? Or just the latter. If you're liable to wind up with a Linux box at the access points anyhow...
I've already got a cable modem and I'm lazy, so I'll let someone else run with this
For real, who has seen/done this? The opportunities for creative mayhem seem mindboggling. Start on Saturday morn, open ur wholesale catalog and take a walk to the neighborhood hardware store....Monday coming around like the wheel has just been re-invented.
This rox, liono.
Claatu, Verata, Nic---sig
there is only very few light outside the main lope ... so its not realy easy to hook up an receiver and sniff the packets on the link :-)
Personally, I wouldn't mind a way to do this sort of thing by shortwave. It would be great for WAN applications between cities [shrug]
"It is a greater offense to steal men's labor, than their clothes"
Alas, poor mini-me will have nothing to hump. (/austin powers 2 reference)
-
ping -f 255.255.255.255 # if only
****Caution - do not look into laser with remaining eye!****
Life is the leading cause of death in America.
If your gonna invent it again, at the very least make it round this time.
This also makes it a lot safer to work with, i.e. you won't burn your eyes out if you accidently look into it."
Ehmm. Modern High efficiency LEDs also carry the "don't look directly into this" warnings. And those things are BRIGHT.
Roger.
power/area on the retina is what matters.
Laser systems can be beamshaped to provide much
higher power densities than incoherent thermal sources.
Hang on, you've said that your antennas cost $40 each, this brings your total to $80. This, with the added wireless cards (costing $100?) would bring the price up to at least $280.
And as these antennas are directional, you lose one of the main advantages of radio and 802.11 - being omni-directional. Surely therefore, even though 802.11 has greater range directionally, over a shorter distance, this LED implementation might be more cost effective?
Just wondering...
--
inirt
that can work over [a distance of] up to 1 kilometre
-- MarkusQ
The most popular stuff seems to be 1200 baud on 2-meter, which is line-of-sight plus repeaters, though there's some 300 baud HF stuff that has more chance of going city-to-city, and some fancier 9600 baud stuff.
Here's some text snagged from The FAQ at TAPR.ORG
TNC (terminal Node Controller)
A TNC contains a modem, a computer processor (CPU), and the associated circuitry required to convert communications between your computer (RS-232) and the packet radio protocol in use. A TNC assembles a packet from data received from the computer, computes an error check (CRC) for the packet, modulates it into audio frequencies, and puts out appropriate signals to transmit the packet over the connected radio. It also reverses the process, translating the audio that the connected radio receives into a byte stream that is then sent to the computer.
Most amateurs currently use 1200 bps (bits per second) for local VHF and UHF packet, and 300 bps for longer distance, lower bandwidth HF communication. Higher speeds are available for use in the VHF, UHF, and especially microwave region, but they often require special (not plug-and-play) hardware and drivers.
Computer or Terminal
This is the user interface. A computer running a terminal emulator program, a packet-specific program, or just a dumb terminal can be used. For computers, almost any phone modem communications program (i.e. Procomm+, Bitcom, X-Talk) can be adapted for packet use, but there are also customized packet radio programs available. A dumb terminal, while possibly the cheapest option, does have several limitations. Most dumb terminals do not allow you to scroll backwards, store information, upload, or download files.
A radio
For 1200/2400 bps UHF/VHF packet, commonly available narrow band FM voice radios are used. For HF packet, 300 BPS data is used over single side band (SSB) modulation. For high speed packet (starting at 9600 bps), special radios or modified FM radios must be used. 1200 bps AFSK TNCs used on 2-meters (144-148Mhz) is the most commonly found packet radio.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
I live in Vancouver, and wintertime reduces the range of these devices to much less than 1 KM. Much of the time when it's raining, visibility isn't that great, and these things require telescopic lenses to get even 1KM range.
:)
I would have to wonder whether this would be much more effective indoors however. It's much more secure (to block packet sniffers, simply close the curtains) than wireless would be, if only you could make the device small enough to put a little blinkenlight in your ceiling that would relay packets around. (in the ceiling because you don't want your cat getting in the way of your data transfers...) It might be a neat project.
"No problem. I have the capacity to do infinite work so long as you don't mind that my quality approaches zero."-Dilbert
I originally posted (laser) this earlier, and I couldn't understand why using a cheap laser diode wouldn't work. I think that it would be perfect infact.
In addition to AirFiber, there's also Terabeam doing building-to-building optical technology. They're in the 100Mbps - 1Gbps speed ranges, with distances of 1km if you don't have fog, or 500 meters if you get fog (they're based in Seattle, so they've had plenty of weather to get real experience with :-) I think there are also a variety of other equipment makers.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
I think these couple of posters assumed the communication ran over a fiber, instead just over the air.
This sounds a wonderful project to try ... I always wanted to get into actually building things (rather than building virtual things / using premade parts that just "plug") ...
...
What this page is missing is an approximate on how much I will have to spend, all things considered. There's a nifty listing for the parts and some pointers on what lenses may cost, but no total or any indication what price-regions we are talking about.
So, could any of the more technically inclined people here give a reasonable estimate on whether to spend $50, $200, or $1000 for one working link ? Thanks in advance
Think of the possibilities! 50mb wireless backbone! And then, like said previously, set up omnidirectional antennas at each relay!
Like eagles on pogo-sticks! -- Glottis
What we need is a "how to hack your old 2x CD-ROM drive into a wireless optical link in just 2 hours"
project.
. .
Hey, flame / mod me away here - I deserve it because I've been looking for a thread in which to post this rejected story sub from a week ago . . But what the heck here it is anyway :
( I was originally going to say this post is well OT because of the distance limitations of the below, but what about using this transmission in a PA system at a stadium, or a train station, where volumes and hence transmission possibilities are greater / farther? And just how much is over the air networking really explored by companies? This story is already dang good and right where it hurts for community and campus networks, but if I were building this kit for business I'd be thinking that planning permission would be the area I'd be researching most. In other words, do the "amateurs" have a real chance at a lead in this technology, especially price / performance wise? After all, you and I personally *don't* have to make budgets for contingent liability just in case the town planning dept. gets difficult. I'm all for guerilla networks - take a look at the below . . )
.This is just like the sad story of napster etc
Company: No, it's completely legal because you can use it for networking, which isn't at all illegal.
Feds: Okay then, implement some filters or something to stop people using it as a weapon
Company: But we'll lose all our customers!
Free Java games for your phone: Tontie, Sokoban
Is that this is just _now_ getting posted, about Ronja, that is.
/. story" you posted (sort the thing "Oldest First", the comment will be on the first page toward the bottom), you will see a comment in there I made in which I included the following link:
If you look through the comments of that "old
http://atrey.karlin.mff.cuni.cz/~clock/r0nj4/
My comment's title was "Homebrew it!" - I noted that Ronja seems to be the best - instead of lasers, ultra-high brightness LED's are used - no great distances here, but aiming doesn't have to be as accurate, fog/rain/birds are less of a problem, the hardware interface is rather simple, and the LED's (and other parts) are cheap!
Makes me wonder what took this so long to be noticed...
Reason is the Path to God - Anon
What company makes this 802.11 equipment? Is it Cisco? I didn't find it on Linksys. Anyway, I would like to look into getting a wireless network set up. Reply to paladinrobot@linuxfreemail.com
http://www.mistersampo.com
DING...
I have a Tv from 1978 that uses acoustics for the remote control... very very old technology, doesnt work very well. was abandoned by most sane companies by 1980. Xerox is far from sane anymore.
Do not look at laser with remaining good eye.
... 10 megabit per second optical data link that can work over up to 1 kilometre.
Does this data link retain it's speed of 10mb/sec even when you get further out towards a kilometer? I'm sure that you probably lose some packets along the way, kind of like CAT5.
void women (int money, time_t time);
This harks back to the days of strings and tin cans from a long time ago where kids would run the string to their next door neighbors. Well, now kids will be making 10mbs wireless connection and instant messaging, video conferencing, or fragging each other in Quake...this is the Advancement in Technology in comparison...
_______________________________
"I'm not Conceited...I'm just a realist..."
first off. i wouldn't consider a LED any less dangerous than a laser. yes, a laser will generally generate a higher powered and more focused beam, but the "dangerous" lasers used in telecomm very often will not exceed 5 to 10dBm.
5mW = 6.99dBm. i wouldn't trust looking at anything with +dbm fairly concentrated source... would you?
on that note, there's lots of info on laser safety at google
a nice pretty chart courtesy of waterloo pointing out what's at risk: your retina, your colour vision, night vision, and skin burns. it's skin burns that are unlikely at such low levels, not eye dammage.
here's an abstract from a ubc page:
"Laser light in the visible to near infrared spectrum (i.e., 400 - 1400 nm) can cause damage to the retina resulting in scotoma (blind spot in the fovea). This wave band is also know as the "retinal hazard region"."
STORY TIME:
i had a co-worker that used to tell me not to worry about the 1500nm range, as "it's only the 1310nm range that you have to be worried about, sheesh." i was nutorious for turning off the laser every time was changing connections.
i probably had a over a mil worth of devices and test equipment on my bench. had a nice automated test (LabView) running. 5dBm Tx laser (MZ pumped up to 10gig internal modulation - yeah baby!), a few km (miles, whatever) of fiber, variable attenuator (VOA), and a nice 10gig Rx (APD).
so anyways, the freeking comm cables (HPIB) controlling the VOA went skitzoid or something. the VOA reset to ZERO attenuation. only a few seconds later, and the APD was fried. (currents jumped from low double/tripple digits to four digits. in mA. so yes, that's amps.)
my stomach sank as i saw the bit error rate (on the BERT) go to 100%. several grand. poof. gone... just like that.
THE POINT OF THE STORY:
i got the idea pretty quick that even components designed to handle that stuff get very cranky very quickly. let alone your eyes. you've only got 1 chance with 'em... don't muck it up.
SIDENOTES:
- from then on in my very short distance tests had a 12dB fixed optical attenuator (less than $20?) instead of relying on a VOA (probably a few grand).
- oh... and i stuck to what i was supposed to be testing: over a few hundred km instead of a few km. heh heh hah... oops.
This is a interesting funny project to buid your 2 computer network using 2 laser toys. http://www.geocities.com/SiliconValley/Lakes/7156/ laser.htm
For transmitting this data inside a room, I'd suggest using infrared LEDs. Not only could the data be bounced off walls (which would eliminate a lot of the bulky shrouds and lenses), but also you wouldn't have an eerie orange glow above your head (and perhaps prevent your cat from getting an epileptic fit).
Anyone else remember anything like this?
This also makes it a lot safer to work with, i.e. you won't burn your eyes out if you accidently look into it."
The site says the EIRP is 10kW -- you will most certainly be hurt if you stare into this thing!
Seems like good advice.
SONY. Because caucasians are just too damn tall.
802.11b is effective in Europe, but the emission regulations mean that we can't use boosters to get the sort of range that hackers do in the US and Australia. We can't even use very high-gain antennae. So this is pretty cool. Remember also that this is only the 2nd model he has build - this could get a lot better with some time, and it is adding to the further congestion of the 2.4Ghz spectrum.
Several years later, I now have dark stuff floating around in my eyes.
He's got Saa floating in his eyes!!! He must be using the power granted from the Dark One!!!
Quick Someone find the Dragon reborn the Forsaken are running loose!!!
You know, I have one simple request...and that is to have 10 megabits of bandwidth with frickin' laser beams sending the signal. Now evidently, my cycloptic colleague informs me that that can't be done. Ah, can you please remind me what I pay you people for? Honestly, throw me a bone here...what do we have?
The author of this paper was laid off from PARC (along with 40 others) last week.